A dead 11-foot-long female pilot whale rolls in the waves on a beach near Bass Harbor on Mount Desert Island on Wednesday, Dec. 19, 2012. Researchers with Allied Whale said there are no obvious physical signs of why the animal died. They have tied the carcass to a large rock and plan to retrieve it on Thursday or Friday. Buy Photo

TREMONT, Maine — Researchers doubt they will find out why a pilot whale died before it washed ashore this week on Mount Desert Island, according to an official with Allied Whale.

The 11-foot pilot whale was reported to Allied Whale, the marine mammal research wing of College of the Atlantic, on Wednesday. Rosemary Seton, the group’s marine mammal stranding coordinator, said the animal is an adult female that is pretty well decomposed.

Pilot whales average about 13 feet in length, she said, but can grow up to 20 feet long. They generally are found in deep water, away from human activity along the coast.

“It’s a species you don’t see so close to shore,” Seton said.

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The animal on a beach near Bass Harbor appears to have shark bites on it, which Seton said probably were inflicted after it was dead. She said Allied Whale has tied the animal to a large rock, to prevent it from floating away with the tide, and planned to return either Thursday or Friday to retrieve it.

She said Allied Whale plans to compost the carcass, which removes the soft tissue, and then to clean and preserve the pilot whale’s skeleton. She said no obvious wounds or other markings are present that could indicate a likely cause of death.

Seton said that, because of the cold weather and the holiday season, Allied Whale does not plan on performing a necropsy to try to determine why the whale died. She said COA is on break and many staff members are away, as well as students. COA does not have an indoor facility where it can do the dissection work more comfortably, which likely would take a while. Even dissecting a relatively small marine mammal like a seal can take hours, she said.

Seton said if the weather were warm and if COA had a ready pool of people to put to work — as it did when Allied Whale dissected a 50-foot sperm whale in Bar Harbor this past August — then maybe a necropsy would be more feasible.

Seton said researchers were unable to determine the cause of death for the sperm whale but added that it did appear to have entanglement scars on its carcass. According to whale researchers and advocates, entanglements with fishing gear are a significant cause of death for marine mammals.

According to the National Oceanic and Atmospheric Administration, more than 30,000 pilot whales are estimated to be in the western North Atlantic Ocean. Pilot whales are not endangered but, like all marine mammals, are a protected species under the federal Marine Mammal Protection Act.